Natural history of impaired glucose tolerance in Japanese Americans: Change in visceral adiposity is associated with remission from impaired glucose tolerance to normal glucose tolerance

Abstract Aims To describe the roles of intra-abdominal fat and its change in the remission of impaired glucose tolerance (IGT) to normal glucose tolerance (NGT). Methods We followed 157 Japanese Americans with IGT at baseline for 10–11 years without external intervention. We measured intra-abdominal and abdominal subcutaneous fat area (IAFA and ASFA) by computed tomography at baseline and at 5–6 years of follow-up. Change in IAFA and ASFA (ΔIAFA and ΔASFA) were calculated by subtracting baseline fat area from 5–6 year follow-up fat area. Glucose and insulin at fasting and during a 75-g oral glucose tolerance test, insulinogenic index (IGI [Δinsulin/Δglucose (30–0 min)]) and homeostasis model assessment for insulin resistance (HOMA-IR) were measured at baseline. Results Fourty-four subjects remitted to NGT. Among those with lower IAFA (≤median 91.31 cm 2 ) and the lowest tertile of ΔIAFA, 45% remitted, while with higher IAFA (>91.31 cm 2 ) and the highest tertile of ΔIAFA, only 12.5% remitted. ΔIAFA was significantly associated with remission to NGT (multiple-adjusted odd ratio [1-SD decrease] 1.93, 95% CI 1.10–3.36) independent of IAFA, ASFA, ΔASFA, IGI, HOMA-IR, age, sex, and family history of diabetes. Conclusions In the natural history of IGT, change in intra-abdominal fat was associated with remission to NGT.